Friday, June 26, 2020

Cervelo Aspero: Issues with Aspero Front Fork

The Cervelo Aspero gravel bike has been fully assembled, but I had some problems initially, as assembly was not so straightforward. More specifically, I had an issue with the front fork Trail Mixer, which is a reversible adapter that is used to adjust the amount of trail.

I found that the concentricity of the adapter hole and the cutout shape of the fork was not good. The cutout on the fork was not deep enough to accept the hub axle properly, causing the insertion of the thru axle to be very difficult. The adapter position had to be manually adjusted to ensure that the thru axle can pass through the adapter and hub axle smoothly.

While trying to solve this issue, I discovered something odd. There is a small bolt that fixes the Trail Mixer to the fork. Under the bolt head, there is also a small washer. As you can see from the pictures below, the washer will get deformed after the hub axle is installed. This condition applies to both sides of the Trail Mixer adapter.

Small washer under the bolt head gets deformed after wheel installation.

The edge of the washer is pressed down by the hub axle, which is odd since it seems to be a design mistake.

As you can see, the hub axle will press down on the edge of the washer once the thru axle is tightened.

Another view of this phenomenon.

The hub axle diameter is measured to be nominal, which is usually about 19 mm.

I have not encountered this problem before on my other thru axle bikes, like the Canyon Endurace or the Fabike C3. Of course those other bikes don't have the Trail Mixer adapter and thus no bolt or washer there.

This condition is unusual since I have not seen any design whereby the washer is designed to be deformed partially after installation. To me, it feels like there was not enough design clearance between the hub axle and the washer.

I first checked with the local bike dealer where I got the bike frame from, but they were unable to answer my question, although they did observe the same deformed washer phenomenon on their Aspero bikes. To them, it was not an issue, and suggested that I contact Cervelo directly if I have any doubts.

Which is exactly what I did, by sending in pictures of the deformed washers as you have seen above. The first reply that I got from Cervelo was that the official drawings of the bike does not have the washers included, although the product manual does have the washer.

Information from the Aspero product manual. The washer can be seen, but it is smaller than what I have on the actual bike.

What I found is that the product manual does show that it has washers, but they are smaller in diameter than what I have on the actual bike. The washer shown in the manual is the same size as the bolt head which would prevent it from being deformed by the hub axle.

Cervelo asked me to try installing the Trail Mixer bolts without the washer, to see if it fits better.

If the washers are included, the bolt length is perfectly flush with the outside of the Trail Mixer.

I removed the washers and tried to tighten the bolt, to fix the Trail Mixer to the fork.

However, due to the missing washer, the bolt will be too long and protrude from the outside of the Trail Mixer.

Also, if the washer is not used, tightening the bolt will cause the carbon surface on the fork to be damaged by the bolt head, as you can see from the depression formed.

Seems that a washer is necessary, in order to prevent damage to the fork during bolt tightening.

After some to and fro, and some discussion within Cervelo, the conclusion is that the washer is designed to be deformed, as per design intention. This is odd, but I accept their explanation even though I am not convinced. Anyway, it does not pose any safety issue and so I will not pursue further.

If you do notice it on your own Aspero, the official explanation from Cervelo is that the washer is meant to be deformed as per design intention.

Unfortunately that was not the only issue that I faced. The other issue was that during the fixing bolt tightening of the front brake adapter (shown below), the washer is too big (or adapter clearance too small). The effect is that when the bolt is being tightened, the washer will interfere with the adapter. The tightening action will also cause the adapter to move sideways, making it very difficult to set the brake caliper position accurately.

It took a lot of trial and error in order to fix the brake caliper position, so as to prevent rubbing with the disc brake rotor. This is another washer issue that I faced on this Aspero.

This problem came about because the brake adapter is a special one from Cervelo, which is designed for the Aspero. The brake adapter is needed when you use the rearward position of the Trail Mixer, which means that the brake caliper needs to be shifted more rearward to match the rearward position of the hub axle and disc rotor. If you use the forward position of the Trail Mixer, you will not encounter this issue.

I was told by Cervelo that the washer of the SRAM fixing bolt is smaller, and thus does not interfere with the brake adapter. I'm using the stock fixing bolt of the Dura-Ace R9170 brake caliper, which is what you see in the picture below. Apparently the washer of the Shimano fixing bolt is larger, which was not taken into account when Cervelo was designing the adapter.

Interference between the washer and the Aspero front brake adapter.

The reply from Cervelo was that they overlooked this, and they will ensure that the adapter works properly with standard fixing bolt and washers from major brake manufacturers, such as Shimano, SRAM, Campagnolo, etc. Good to know that they will make improvements to this.

In summary, I faced two washer problems with the Aspero, but luckily none of it was critical to safety or installation. I was glad that Cervelo was able to give me an answer, and that they are now aware of these issues, and will make improvements.

Friday, June 19, 2020

Fnhon DB11: Elosix 29 cm 2 Bolt Handlepost

My latest folding bike project is the Fnhon DB11, which is a 1x11 speed folding bike with 451 wheels, premium XTR brakes and some other goodies.

Among the new components that I used was the latest Fnhon handlepost, which has a smooth joint like Tern Physis handleposts. This gives it a better appearance and also looks more high-end. However, after using it, I found that it seems to be slanted to one side.

What I mean by slanted is that the handlepost is not perfectly vertical, when the front wheel is perfectly vertical. There is a sideways tilt of the handlepost, which causes the handlebar to be tilted as well. The end result is that one side of the handlebar will be higher than the other, when riding straight. This effect is not much, but it is enough that I can feel the difference.

When the front wheel is vertical, the top of the handlepost can be seen offset to the right side, due to the tilt of the handlepost. This offset also causes the handlebar to be higher on the left side than the right side.

Although riding and folding the bike is normal, this tilting of the handlebar gives me a weird sensation that I cannot get used to. I am probably more sensitive to these kind of non-symmetrical effects, as I always set up my components to be as perfectly symmetrical as possible.

Examples: height and angle of road shifter hoods needs to be the same on left and right side, handlebar needs to be perfectly perpendicular to front wheel, saddle needs to be pointed perfectly straight, etc.

Other than the handlepost tilt, I also found that the handlebar height is a little higher than what I prefer. It is VERY difficult to find a handlepost height that is shorter than the common 31.5 cm Fnhon handlepost, as most other handleposts are taller. I used to have a shorter 27 cm handlepost, but I can't find it on Taobao any more.

After much searching, I finally managed to find a seller who has a shorter handlepost available. It also needs to be the 2 bolt or 4 bolt kind (not QR or T-shaped type), and also inward folding. Apparently the brand is Elosix, but it could be anything actually.

New shorter Elosix handlepost on the left, versus the common 31.5 cm Fnhon handlepost on the right. Both of these are the traditional Dahon/Fnhon design, not the new smooth type from Tern/Fnhon.

New handlepost has a rhino logo printed on the top clamp, and uses a bolt with a different head.

Base of the handlepost looks almost the same, but with a different clamp bolt.

Looks almost the same from the bottom.

The lever looks the same, but the plastic safety catch is different.

As mentioned, the lever looks to be from the same mold. Even the circular debossed feature is there.

Internal clamp design is different. Shown on the left is the new Elosix handlepost.

Elosix design is simpler, with no frame to hold the sliding bolt. This allows the internal space of the handlepost to be seen.

Fnhon 31.5 cm handlepost has an actual height of about 33.8 cm. The difference is due to how the height is defined (from clamp joint) vs how it is measured (from base). Strange but true.

New Elosix handlepost (claimed height 29 cm) has an actual height of 31 cm. About 2.8 cm shorter than the Fnhon handlepost.

Traditional Fnhon 31.5 cm handlepost weighs 565 grams

New Elosix 29 cm handlepost weighs 518 grams, a difference of about 47 grams.

However, note that this comparison above is between the traditional construction of the Fnhon handlebar and the Elosix handlepost, which look almost similar. The handlepost that I installed on the Fnhon DB11 is the new type of Fnhon handlepost, which requires a longer compression bolt.

Therefore, a more complete weight comparison is as shown:

Weight comparison of handlepost + compression bolt:
Traditional Elosix 2 bolt type (29 cm) + compression bolt = 518 + 45 = 563 grams
Traditional Fnhon 2 bolt type (31.5 cm) + compression bolt = 565 + 45 = 610 grams
New Fnhon 4 bolt type (31.5 cm) + longer compression bolt = 552 + 68 = 620 grams.

In this case, changing from the new Fnhon 4 bolt type to the shorter Elosix 2 bolt type gives a weight saving of about 57 grams, which is only about 0.6% of the whole bike's weight.

New Fnhon 4 bolt type handlepost. Wider clamp but also more weight.

From left to right: Elosix 29 cm 2 bolt, New Fnhon 31.5 cm 4 bolt, Traditional Fnhon 31.5 cm 2 bolt.

The height of the new Fnhon 4 bolt type and traditional Fnhon 2 bolt type is almost the same, since both are labeled as 31.5 cm height.

After installing the new Elosix handlepost, I found that the tilting is still present.

Front wheel is perfectly vertical, but there is some tilting of the handlepost towards the right.

Strangely, there is still some tilting of the handlepost and handlebar after swapping to the new Elosix handlepost. In this case, it is likely that the handlepost may not be the issue after all. Maybe the fork legs are bent, or the frame head tube is tilted, which can also cause the same effect. It is difficult to conclude definitively since the tilting is small, and I cannot measure the parts accurately.

Regardless, the handlebar height is now reduced, which I much prefer over the previous one. Maybe it is because I am used to riding drop bar bikes with a low handlebar, therefore I am not used to riding flat handlebar bikes with a higher handlebar.

With the handlebar transplanted onto the new Elosix handlepost.

As the handlepost is shorter, the handlebar is located differently when folded down. I will need a new protective sticker on the fork leg to prevent the handlebar from hitting the fork leg.

New protective sticker pasted on the fork, to prevent scratches between the handlebar and the fork leg during folding.

Picture with the shorter handlepost! Although it is only about 2.8 cm lower, it does make a difference both ergonomically and visually.

Updated bike component specifications, with shorter and lighter Elosix handlepost. Bike weight without pedals and kickstand is now 8.8 kg.

I am happy with this change of handlepost, as the lower handlebar enables a more sporty riding position which I prefer. Although the handlepost tilting issue is not 100% solved, it is less obvious and no longer annoys me so much. Not sure if my previous folding bikes had this problem, but I have not noticed it before.

Sunday, June 14, 2020

Wahoo Kickr Core: Introduction

In normal times, indoor bicycle trainers are not hot sellers. They are usually used only when the weather makes it impossible or unpleasant to cycle outdoors, such as areas with cold winters.

However, amid the ongoing global pandemic, indoor bike trainers have surged in popularity. Due to the severe limitations on outdoor cycling (and most forms of outdoor activities), cyclists are finding ways to continue cycling indoors. This sudden surge in demand for bike trainers led to them being sold out everywhere, in stores or online.

In the first place, bike trainers are not items with high stock levels, as they move really slowly. Now, with many people looking to buy them, even stores with substantial stock (>10 units) will run out of stock very quickly.

I am also one of those who want to continue cycling indoors, which is why I found a way to make my Cervelo Aspero fit on the Minoura LR340 Bike Trainer. However, I am not a big fan of wheel-on-roller bike trainers, or in other words, dumb bike trainers. That is because there are various downsides to these kind of dumb trainers.

Disadvantages of dumb bike trainers, compared to direct drive bike trainers:
1) Noisy.
2) Heats up fast.
3) Gives off a burning smell from the heated tire rubber.
4) Very high wear rate on the tire (unless you use dedicated bike trainer tires).
5) Sheds rubber bits from the tire as it wears out.
6) Riding characteristics differ greatly from actual road riding as the rear wheel cannot freewheel properly or carry momentum.

The Minoura Thru Axle Adapter is just a temporary solution, while I find a better long term solution for a direct drive smart bike trainer. Although I tried to buy a direct drive bike trainer in early April, it was already too late, as there was no stock of direct drive bike trainers anywhere.

My only option was to place a pre-order and be patient. I was given an estimated delivery date of end May, which is the earliest date I could find. This is for one of the highest rated direct drive smart bike trainers, the Wahoo Kickr Core. This decision was no doubt helped by the super detailed review by DC Rainmaker.

The feature that really stood out for me was the low noise level of the trainer, which is really important for me. Being a direct drive type was also critical, in order for a more realistic ride. For more details, you can check out the review by DC Rainmaker, or read on below for a more simplified version.

This Wahoo Kickr Core actually arrived ahead of schedule, in the middle of May. I was expecting the delivery schedule to be delayed to June, due to the production and logistics difficulties around the world. It was a pleasant surprise to receive the Kickr Core early, as it means more time to use it!

The Wahoo Kickr Core is here! It is a big and heavy box.

As a direct drive bike trainer, it replaces the rear wheel of the bike, which I think is a great system.

You get lots of power cables, to fit the power sockets of every region.

In Singapore, this is what we need. The power adapter is shown on the left. Yes this smart trainer needs to be plugged in, unlike dumb trainers which are not powered.

Main trainer unit all wrapped up, as it still requires some assembly.

It is important to connect the smart trainer to the Wahoo app for some updates.

Here is the freehub body! Standard Shimano splines, for 11 speed road cassettes. The cassette is not included.

Here are the legs for the bike trainer. The long one attaches to the front, while the short one is attached to the rear.

Lots of small parts and adapters included, plus the manual.

4 bolts to attach the 2 legs to the main trainer unit.

The hole on the trainer legs are actually square holes, which is unusual.

The square hole matches to the square head of the bolt, to prevent rotation during tightening of the nuts.

Bolts are inserted from the bottom, and are tightened with a nylon lock nut on top.

The nuts are covered with a black plastic cap, for better appearance and to prevent rust due to sweat.

The adapters provided by Wahoo will cover most conventional bikes. The steel QR axle is also provided.

Self-explanatory graphics, very easy to understand. Adapts between 130/135 mm QR type, or 
142/148 x 12 mm thru axles. 148 mm means you can put your Boost spec MTB on this bike trainer!

As always, tighten the QR axle or thru axle fully and securely.

And here is the secret to the quiet operation of the Kickr Core. A new belt drive system that lowers the driving noise compared to previous models.

The cylinder with the arrows is the flywheel, and that is what makes this whole bike trainer so heavy.

Kickr Core assembled! Driving the freehub body will move the belt, which rotates the flywheel via a pulley ratio that makes the flywheel spin much faster than the cassette.

According to the manufacturers of direct drive bike trainers, a bigger flywheel is an advantage as it can replicate the road riding feel more realistically. However, this also makes the whole bike trainer really heavy, as there is a big flywheel attached to it. If you need to move the bike trainer around often, it will be quite inconvenient.

Wahoo Kickr Core weight as measured: 19 kg without cassette

I also checked out the freehub body, to determine the engagement angle. Normally a smaller engagement angle means a shorter lag time between pedaling and the wheel actually moving. However, it also depends a lot on the gear ratio and also the type of usage. For me, 15 degrees or less is sufficient for on-road riding, while for off-road riding, it needs to be less than 10 degrees.

The freehub on the Kickr Core has a 15 degree engagement angle, or 24 clicks per rotation of the freehub body. The actual points of engagement is unknown, but it is most probably 2 points of engagement, as this is usually sufficient for strength.

So far I have set up the Kickr Core, and it was easy. The adapters are easy to identify and swap. Next step is to install the cassette, attach a bike, and connect it to an app for some indoor riding! Watch for the next blog post where I will show how I attach my bikes to the Kickr Core.